   (reify
     om/IRender
     (render [_]
-      (dom/div #js {:className (piece-class-name p)} nil))))
+      (dom/div #js {:className (piece-class-name p)} nil))
+    om/IDisplayName
+    (display-name [_]
+      "piece")))
 
 (defn square [[id p selected] owner {:keys [click-chan]}]
   (reify

                (om/set-state! owner :selected nil))
              (if (b/in (deref board) new-selection)
                (om/set-state! owner :selected new-selection))))
          (recur))))))

            :id        id
            :onClick   #(put! click-chan id)}
       (if p
         (om/build piece p))))
    om/IDisplayName
    (display-name [_]
      "square")))

(defn board [{:keys [board] :as app-state} owner]
  (reify
